Q:
__________ could be utilized as a point sensor by measuring a time pulse of __________ takes to echo back to the transmitter. It is similar in principle to a radar.
Answer & Explanation
Answer: D) Ultrasound
Explanation: Ultrasounds are sound waves with frequencies which are greater than the upper audible limit of human hearing. Ultrasound is no different from ‘normal’ (audible) sound in its physical properties, except in that humans couldn’t hear it. Ultrasound devices operate with frequencies from 20 kHz up to several gigahertz.
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